Conventionally, a stereoscopic image taking apparatus having an optical system illustrated in FIG. 16 has been known (PTL 1).
The optical system is configured so as to pupil-split, by a mirror 4, object images which have passed through different regions of a main lens 1 and a relay lens 2 in left and right directions to form the object images on imaging devices 7 and 8 via focusing lenses 5 and 6.
Portions (A) to (C) in FIG. 17 are diagrams illustrating separation states of an image to be formed on imaging devices due to such differences as a focal point of a lens in front of an object, focusing (best focus), and a focal point of a lens behind an object. Incidentally, in FIG. 17, the mirror 4 illustrated in FIG. 16 is omitted for comparison of differences in separation due to focus.
As illustrated in Portion (B) in FIG. 17, focused images of pupil-split images are focused on the same position on the imaging device (are coincide with each other), but as illustrated in Portions (A) and (C) in FIG. 17, images obtained by the focal point of a lens in front of an object and the focal point of a lens behind an object are focused on different positions on the imaging device (are separated from each other).
Accordingly, a left viewpoint image and a right viewpoint image (a 3D image) which are different in parallax according to an object distance can be captured by acquiring object images pupil-split in left and right directions via the imaging devices 7 and 8.
In addition, as the conventional art relating to the stereoscopic image taking apparatus, there is one described in PTL 2.
Further, a digital camera which extracts a person-image region from an image to apply different sharpness corrections to the extracted person-image region and the remaining background-image region other than the person-image region, as image processing providing depthwise feeling or stereoscopic feeling has been proposed (PTL3).